Transition metal carbene complexes, such as ruthenium carbene complexes called Grubbs' catalyst and molybdenum carbene complexes and tungsten carbene complexes called Schrock's catalyst, are known as highly-active catalysts for metathesis reactions (hereinafter frequently referred to as “metathesis catalyst”) and are widely used.
Among the transition metal carbene complexes, molybdenum carbene complexes and tungsten carbene complexes exhibit extremely high activity as metathesis catalysts, and may promote metathesis reactions stereospecifically when the substituent and the ligand on the metal are suitably selected, as disclosed for example in JP2002504487A (PTL 1). Thus, various studies have been made on molybdenum carbene complexes and tungsten carbene complexes.
However, molybdenum carbene complexes and tungsten carbene complexes are less stable in air than ruthenium carbene complexes or the like. Thus, molybdenum carbene complexes and tungsten carbene complexes (hereinafter frequently referred to as “molybdenum carbene complexes, etc.”) are not easy to handle (or are poor in handleability), which is a problem.